Coffee beverages contain chlorogenic acids, a kind of polyphenol, such as chlorogenic acid, coffeic acid and ferulic acid. The chlorogenic acids are reported to have excellent physiological activities such as an hypotensive effect. Increasing the ingestion of chlorogenic acids is efficient to allow the physiological activities to be sufficiently exhibit.
Green coffee beans contain a large amount of chlorogenic acids; however, coffee beverages obtained from green coffee beans do not have the proper coffee taste and flavor. In contrast, coffee beverages obtained from roasted coffee beans have good coffee taste and flavor; however, an amount of chlorogenic acids is reduced by roasting.
Therefore, as a coffee product which contains chlorogenic acids at a high concentration and has good coffee taste and flavor, for example, proposed is a coffee product obtained by grinding a mixture containing green coffee beans and roasted coffee beans in a predetermined ratio, and then subjecting the mixture to extraction and drying (Patent Document 1). Furthermore, proposed is a packaged coffee beverage, in which coffee extracts obtained from dark roasted coffee beans and light roasted coffee beans are mixed and the ratio of chlorogenic acids to tannin and the ratio of dichlorogenic acids to chlorogenic acids are controlled to fall within specific ranges (Patent Document 2). Moreover, a process for producing coffee beans reduced in the content of hydroxyhydroquinone, which inhibits the hypotensive effect of chlorogenic acids, is proposed (Patent Document 3).